diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -590,8 +590,9 @@
       [[fallthrough]];
     }
     case tok::kw_case:
-      if (Style.isVerilog() ||
+      if (Style.isProto() || Style.isVerilog() ||
           (Style.isJavaScript() && Line->MustBeDeclaration)) {
+        // Proto: there are no switch/case statements
         // Verilog: Case labels don't have this word. We handle case
         // labels including default in TokenAnnotator.
         // JavaScript: A 'case: string' style field declaration.
@@ -1620,7 +1621,11 @@
     // e.g. "default void f() {}" in a Java interface.
     break;
   case tok::kw_case:
-    // In Verilog switch is called case.
+    // Proto: there are no switch/case statements.
+    if (Style.isProto()) {
+      nextToken();
+      return;
+    }
     if (Style.isVerilog()) {
       parseBlock();
       addUnwrappedLine();
@@ -2100,6 +2105,11 @@
       parseNew();
       break;
     case tok::kw_case:
+      // Proto: there are no switch/case statements.
+      if (Style.isProto()) {
+        nextToken();
+        return;
+      }
       // In Verilog switch is called case.
       if (Style.isVerilog()) {
         parseBlock();
diff --git a/clang/test/Format/case.proto b/clang/test/Format/case.proto
new file mode 100644
--- /dev/null
+++ b/clang/test/Format/case.proto
@@ -0,0 +1,15 @@
+// RUN: grep -Ev "// *[A-Z-]+:" %s \
+// RUN:   | clang-format -assume-filename=case.proto -style=Google \
+// RUN:   | FileCheck -strict-whitespace %s
+
+syntax = "proto2";
+
+package foo.bar;
+
+message Baz {
+  optional int64 fred = 1;
+// CHECK: {{^\ {2}required}}
+required string case = 2;
+// CHECK: {{^\ {2}repeated}}
+repeated int32 fizz = 1;
+}